Exogenous ascorbic acid derivatives and dehydroascorbic acid are effective antiviral agents against Turnip mosaic virus in Brassica rapa
Exogenous ascorbic acid derivatives and dehydroascorbic acid are effective antiviral agents against Turnip mosaic virus in Brassica rapa
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DOI：
10.1007/s10327-013-0439-5
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发表时间：
2013-05-01
影响因子：
1.2
通讯作者：
Inukai, Tsuyoshi
中科院分区：
文献类型：
--
作者：
Fujiwara, Ayaka;Shimura, Hanako;Inukai, Tsuyoshi
植物在受到病毒感染时，可以激活转录后基因沉默（PTGS）作为一种免疫系统。病毒可以通过产生RNA沉默抑制子（RSS）蛋白来干扰该系统;大多数RSS与病毒小干扰RNA（siRNA）结合。我们以前报道过抗坏血酸（阿萨）能够在体外干扰病毒siRNA和病毒RSSs之间的结合。因此，我们预期AsA处理的植物将表现出一定的耐受病毒感染，因为宿主PTGS将被阿萨加强。芜菁用芜菁花叶病毒（Turnip mosaic virus，RVV）接种芜菁，接种后1h分别用阿萨衍生物、1（+）-抗坏血酸2-硫酸二钠盐（AsA-SO_4）、1（+）-抗坏血酸棕榈酸酯（AsA-SO_4）和脱氢抗坏血酸（DHA）处理。与未处理的对照相比，AsA-SO 4和AsA-DHA处理后接种叶片上的感染位点数量减少了约40%，DHA处理后减少了80%。通过酶联免疫吸附试验证明，定期喷洒阿萨衍生物和DHA后，病毒积累显著减少。在离体叶片试验中，阿萨在细胞中明显起病毒抑制剂的作用。此外，我们证实DHA也在沉默途径中起作用，因为在拟南芥沉默缺陷双突变体dcl 2/dcl 4中没有观察到其抗病毒作用。基于这些结果，我们得出结论，阿萨衍生物和DHA可以显着减少病毒感染和积累，我们可以开发这些化合物作为一个实用的抗病毒剂在未来。
Plants may activate posttranscriptional gene silencing (PTGS) as an immunity system when they are infected with viruses. Viruses may in turn interfere with this system by producing RNA silencing suppressor (RSS) proteins; most RSSs bind to viral small interfering RNAs (siRNAs). We previously reported that ascorbic acid (AsA) has the ability to interfere with the binding between viral siRNAs and viral RSSs in vitro. We thus expected that AsA-treated plants would show some tolerance to virus infection because the host PTGS will be strengthened by AsA. Brassica rapa subsp. rapa was inoculated with Turnip mosaic virus and treated with the AsA derivatives, l(+)-ascorbic acid 2-sulfate disodium salt dihydrate (AsA-SO4), l(+)-ascorbyl palmitate (AsA-Pal) and dehydroascorbic acid (DHA) at 1 h postinoculation. The number of infection sites on inoculated leaves decreased by around 40 % after AsA-SO4 and AsA-Pal treatments and by 80 % after DHA treatment compared with the untreated control. As evidenced by an enzyme-linked immunosorbent assay, viral accumulation was significantly reduced after regular sprays with the AsA derivatives and DHA. In a detached leaf assay, AsA clearly functioned as a viral inhibitor in cells. Additionally, we confirmed that DHA also worked in the silencing pathway because its antiviral effect was not observed in the silencing-defective double mutant dcl2/dcl4 of Arabidopsis thaliana. On the basis of these results, we concluded that the AsA derivatives and DHA can significantly reduce viral infection and accumulation and that we can develop those compounds as a practical antiviral agent in the future.